1550 nm low-noise DFB laser

LD101 - 1550 nm low-noise DFB laser
LD101 - 1550 nm low-noise DFB laser LD101 - Relative intensity noise LD101 - Spectral linewidth LD101 - Functional diagram

Koheron LD101 is a 1550 nm, low-noise, DFB laser with integrated current driver, photodetector and RF modulation. It works on a single 3.3V power supply and is designed to be mounted on a standard M6 metric breadboard. Laser current is adjusted with a precision trimmer ranging from 0 to 55 mA. The LD101 features an AC-coupled modulation input for current modulation. The internal photodetector includes a transimpedance amplifier with a gain of 2 V/mA and 40 MHz bandwidth. The LD101 has a typical spectral linewidth of 5 MHz.

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Laser diode
Wavelength 1550 nm
Optical power (30 mA current) 3 mW
Spectral linewidth 5 MHz (typ.) / 8 MHz (max.)
Integrated optical isolation 30 dB
Fiber output 1 m SM fiber with FC/APC connector
Current monitoring gain 40 mV/mA
Limit 55 mA
AC modulation cut-off frequency 1.6 kHz
Gain 20 mA/V above 100 kHz
Internal photodetector
Bandwidth 40 MHz
Gain 2000 V/A
Output impedance 50 Ω
Power supply 3.3 V - 5 V
I/O SMA for modulation and internal photodetector
Outside dimensions (excl. fiber) 64 mm x 45 mm x 14 mm
Weight 21 g
Operating temperature 0 - 50 °C

Functional diagram

LD101 Laser functional diagram


Relative intensity noise

We characterized the laser relative intensity noise (RIN) for different operating currents. In all measurements, the same optical power (1 mW) was sent to the photodetector to maintain the same shot-noise floor.

Relative intensity noise

Spectral linewidth

We measured the LD101 spectral linewidth using the self-homodyne method with a 10 km fiber delay. The figure below shows the power spectral density of the interference signal:

Spectral linewidth

Modulation input

The graph below shows the frequency response of the AC-coupled modulation input at 40 mA current and 1 Vpp modulation.

Modulation input response

Example: 100 kHz triangle

We modulated the laser current with a 100 kHz triangle wave. The graph below shows in yellow the modulation signal, in blue the monitoring output and in green the laser output observed with a PD100-DC photodetector.

Modulation ramp

Internal photodetector output

The graph below shows the frequency response of the internal photodetector output. Bandwidth at 3 dB is about 40 MHz.

Internal photodetector output frequency response

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